Big Ben's Panorama Tutorials

Dynamic Range

Evaluating Results

The images I have included here covered the maximum detectable range of
variation. A visual inspection of the negatives showed very small
variations for another 4 EV however by this stage, the variations were so
small and noise/film grain so great that any real detail would have been
completely useless. The images below show an enlargement of the
relevant edge of the grey rectangle from the lowest and highest exposures
recorded

Grey -> White, EV 21

Black -> Grey, EV 1

Noise largely a result of
film grain

Noise is a result of:

Noise from scanner

Texture of paper

Film Grain

Normalised Data

Since all of the images displayed a variation in density
corresponding to a change in exposure, I could claim that the film has a
dynamic range of 20EV The compression in the highlight detail however
make it impractical to get usable image information out of the entire range.
Before evaluating the raw data I'll normalise it to cover the full range of
pixel values (0-255)

Relative EV

1

2

3

4

5

6

7

8

9

10

11

Black

0.00

0.37

1.06

3.69

12.68

35.76

77.16

118.72

154.56

185.25

208.84

Grey

0.63

2.51

7.72

24.09

59.33

102.54

140.49

173.03

198.42

220.88

234.69

White

6.99

20.22

44.07

83.05

124.82

161.81

189.67

213.24

230.30

240.64

246.39

Relative EV

12

13

14

15

16

17

18

19

20

21

Black

226.77

237.78

244.31

248.21

250.64

251.86

252.68

253.49

254.02

254.27

Grey

242.67

247.26

250.38

252.00

252.87

253.27

253.85

254.34

254.66

254.88

White

249.98

251.96

253.06

253.68

254.10

254.30

254.60

254.82

254.91

255.00

Dynamic Range Calculations

Subsequent increase in exposure results in >1 increase in
pixel value

Criterion: The image displays a change in pixel value
of at least 1 for a subsequent increase/decrease in exposure.

Dynamic Range = 16 Stops

Relative EV

1

2

3

4

5

6

7

8

9

10

11

Grey - Black

0.63

2.14

6.67

20.40

46.65

66.78

63.32

54.31

43.87

35.62

25.85

White - Grey

6.36

17.71

36.34

58.96

65.49

59.27

49.19

40.21

31.88

19.76

11.70

Relative EV

12

13

14

15

16

17

18

19

20

21

Grey - Black

15.91

9.48

6.07

3.79

2.23

1.41

1.18

0.86

0.64

0.61

White - Grey

7.31

4.70

2.68

1.68

1.22

1.02

0.75

0.47

0.24

0.12

1EV increase in exposure results in >1 increase in pixel value

Criterion: 1EV change in exposure results in an
increase in pixel value of at least 1.

Dynamic Range = 14 stops

Relative E.V

1

2

3

4

5

6

7

8

9

10

11

Mean PV

0.63

2.51

7.72

24.09

59.33

102.54

140.49

173.03

198.42

220.88

234.69

EV(n) - EV(n-1)

-

1.88

5.22

16.37

35.24

43.21

37.95

32.55

25.39

22.45

13.81

Relative E.V

12

13

14

15

16

17

18

19

20

21

Mean PV

242.67

247.26

250.38

252.00

252.87

253.27

253.85

254.34

254.66

254.88

EV(n) - EV(n-1)

7.98

4.59

3.12

1.62

0.87

0.40

0.58

0.49

0.32

0.21

Given the extremely broad "shoulder" of the characteristic
curve for this film it is difficult to pinpoint an exact figure for the
dynamic range. For the sake of argument I will take the average of the
two values calculated above, i.e. 15EV